1. Field of the Invention
The present invention relates to a projection device and a projection control method which are suitable for, e.g., a projector of a DLP (registered trademark), or the like.
2. Description of the Related Art
Conventionally, as described in Jpn. Pat. Appln. Publication No. 2004-279817, consideration has been given to a technology of a projector which arranges, to improve uniformity of an illuminance distribution, a plurality of light emitting diodes (LED) having similar color lights positioned on lattice points of a roughly regular triangular lattice shape on a substrate to constitute a LED array, modulates an illumination light from the LED array whose illuminance distribution has been made uniform via a transmissive type liquid crystal display (LCD) panel, and projects a color light modulated through the LCD on to a screen by a projection lens optical system, thereby obtaining a projected light of improved uniformity of illuminance distribution.
According to the technology of the above Patent Document, however, even if the illuminance distribution is uniform at a point in time when light is emitted from the LED array as a light source, the illuminance distribution of an image actually projected on the screen is not always uniform.
For example, this situation is conspicuous when a plane of the screen is arranged not vertically but greatly obliquely to a projected optical axis, and a distance from the projection device varies from one projected part to another, such as when trapezoidal correction is made, when the trapezoidal correction is accompanied by a change in image density, or the like. In consequence, while the uniform illuminance distribution is exhibited at the light source, display quality of the actually projected image is greatly degraded.
The present invention has been made with the foregoing situation in mind, and it is an object of the invention to provide a projection device and a projection control method capable of always making uniform an illuminance distribution of an actually projected image irrespective of a projection situation.